Search PubMed⌕ Search

Biomedical subjects

J Lane

Publications and source records attributed to J Lane.

At least 91 records · Page 5Linked to original sources
PubMed1989

Liver tryptophan pyrrolase. A major determinant of the lower brain 5-hydroxytryptamine concentration in alcohol-preferring C57BL mice.

The lower brain 5-hydroxytryptamine concentration in alcohol-preferring C57BL, compared with -non-preferring CBA, mice is caused by a decrease in circulating tryptophan availability to the brain secondarily to a higher liver tryptophan pyrrolase activity associated with a higher circulating corticosterone concentration. Activity or expression of liver tryptophan pyrrolase and/or their induction by glucocorticoids may be important biological determinants of predisposition to alcohol consumption.

Alcoholism↗
PubMed1989

The MRL +/+ mouse: a new model of tubular aggregates which are gender- and age-related.

Congenic mice of the MRL +/+ substrain provide an animal model for study of tubular aggregates in skeletal muscle. Tubular aggregates appear limited only to males of the MRL +/+ strain and are not found in other strains, including MRL +/-, MRL lpr/lpr, BXSB/MpJ, BALB/c, SJL/J, AJ, or C3H HEJ. This strain-specific occurrence, and the gradually increasing abundance of tubular aggregates after 6 months of age until virtually all type II myofibers are affected by 2 years, implies that both genetic and developmental factors are necessary for the occurrence of tubular aggregates. These two factors are not sufficient, however, since hormonal alteration by male castration nearly completely prevents the expression of tubular aggregates. Parallels are drawn with how expression of tubular aggregates is limited largely to males in diverse acquired and hereditary human neuromuscular disorders.

Animals↗
PubMed1989

Anti-SS-A/Ro SS-B/La antibodies bind to neonatal rabbit cardiac cells and preferentially inhibit in vitro cardiac repolarization.

The neonatal lupus syndrome is the most common cause of isolated congenital heart block. There is, at present, little information about the putative role of anti-SS-A/Ro SS-B/La antibodies in the pathogenesis of congenital heart block in the neonatal lupus syndrome. Using an in vitro experimental model, the present study was designed to test the hypothesis that IgG antibodies in the sera of anti-SS-A/Ro SS-B/La-positive mothers of infants with isolated congenital heart block bind to and affect the transmembrane action potential of rabbit cardiac tissue. The results demonstrate a preferential inhibition of membrane repolarization (ADP-50 and ADP-90) and staining of cardiac cells within the neonatal, in contrast to the adult, rabbit heart by sera and IgG-enriched fractions from anti-SS-A/Ro SS-B/La-positive individuals. The results of the electrophysiologic studies demonstrate a pathophysiologic role for the IgG fraction of anti-SS-A/Ro SS-B/La-positive maternal sera in inhibiting neonatal rabbit cardiac repolarization. It is possible that antibodies to similar determinants expressed on the cell membrane of cardiac-conducting cells also may play a pathophysiologic role in the development of idiopathic congenital heart block in humans.

Animals↗
PubMed1989

Primary carcinoma of the gallbladder: a pictorial essay.

This paper is an overview of the imaging characteristics of primary carcinoma of the gallbladder, based on the premise that more general knowledge of the imaging patterns of the primary tumor and its modes of spread might increase the likelihood of accurate preoperative diagnosis of this lesion. Primary tumor patterns discussed and illustrated are: (I) an intraluminal mass, (II) focal or diffuse thickening of the gallbladder wall, and (III) replacement of the gallbladder by a mass. Illustrated patterns of tumor spread include direct extension and lymphatic and hematogenous metastases.

Adenocarcinoma↗
PubMed1989

Treatment of bone weakness in patients with femoral neck fracture by fluoride, calcium and vitamin D.

Twenty-three of 46 patients, aged 56 to 95 years, with fracture of the femoral neck (FNF) completed the first trial of 10 months treatment with oral sodium fluoride 60 mg and calcium 1800 mg on alternate days and 1 micrograms of vitamin D1 daily. Pre-treatment and post-treatment biopsy specimens and microradiographs of the iliac crest and metacarpal and spinal radiographs were evaluated together with biopsy material from seven untreated age-matched controls with FNF. In 17 patients the treatment improved the amount and quality of trabecular bone. Cortical thickness increased in nine patients and there were no losses of amount or mineralisation. The treatment was well tolerated by most patients and there were no major side-effects or signs of bone demineralisation. The study also revealed an unexpected rapid post-fracture deterioration of bone tissue in untreated FNF patients; thus there is an increased risk of further fractures which calls for the use of an effective treatment to increase bone mass.

Aged↗
PubMed1989

Cooperation of adipocytes and endothelial cells required for catecholamine stimulation of PGI2 production by rat adipose tissue.

Disturbances of prostaglandin I2 (PGI2, prostacyclin) production by adipose tissue contribute to the pathogenesis of diabetic ketoacidosis and may contribute to the pathogenesis of hypertension and vascular disease. We studied the cellular basis of PGI2 production in adipose tissue, measured as release of 6-keto-PGF1 alpha in response to epinephrine. Adipocytes did not produce PGI2 when nonfat cells were removed by repeated washing. The nonadipocyte cellular constituents of adipose tissue (nonfat cells) did not produce PGI2 in the absence of adipocytes. Both adipocytes and nonfat cells were required for PGI2 production in response to epinephrine. Adipocytes pretreated with 0.2 mM aspirin to inhibit PGH synthase nevertheless promoted PGI2 production when mixed with nonfat cells. Nonfat cells preincubated with aspirin did not produce PGI2 when mixed with adipocytes. The nonfat cells converted arachidonic acid to PGI2 but adipocytes did not. Epinephrine stimulated lipolysis and PGI2 production in a dose-dependent parallel manner, but the responses were distinct above 10(-6) M. Characterization of the nonfat cells by fractionation on a Percoll density gradient followed by measurement of angiotensin-converting enzyme activity and 6-keto-PGF1 alpha production indicated that the nonfat cells were predominantly vascular endothelial cells. We conclude that catecholamine-stimulated PGI2 production in adipose tissue results from the cooperation of adipocytes and vascular endothelial cells. The adipocytes provide arachidonic acid, which is converted to PGI2 by the vascular endothelial cells. Because adipose tissue is located near blood vessels throughout the body, adipocytes may be an important source of arachidonic acid for vascular endothelial cells in various circumstances in health and disease. Our findings raise the possibility that adipocytes may, under some circumstances, release arachidonic acid into the systemic circulation where it is used by vascular endothelial cells throughout the body to produce PGI2 and other eicosanoids.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Work profiles of research statisticians.

Analysis of work profiles of 138 persons who had published in the Journal of the American Statistical Association showed this study group published more often than 128 members of the Association and tended to enjoy research, being less interested in the theoretical contribution of their work and more interested in the likelihood of work being published. Administrative and committee duties were impediments for those who published.

Attitude↗
PubMed1988

Soft-tissue sarcomas of the extremities: comparison of MR and CT in determining the extent of disease.

A prospective comparison of the accuracy of MR and CT in determining the anatomic extent of disease was carried out in 40 patients who had histologically proved soft-tissue sarcomas of the extremities. Tumor resection, performed by using either en bloc excision or amputation in all patients, allowed detailed pathologic verification of imaging findings. Image analysis included measurement of maximum tumor dimensions, notation of tumor position in relation to deep fascia, recording of anatomic compartment and individual muscle involvement, and documentation of the spatial relationships between tumor, neurovascular structures, underlying bones, and joints. MR and CT were equally accurate in measurement of maximal tumor diameter, detection of tumor depth, and delineation of tumor, neurovascular, osseous, and articular relationships. Evaluation of anatomic compartment and individual muscle involvement was more accurately accomplished with MR imaging; nine (23%) of 40 MR studies showed tumor involvement of one or more individual muscles that appeared normal in CT scans. These results suggest that MR imaging may be the staging procedure of choice in patients with soft-tissue sarcomas of the extremities.

Adolescent↗
PubMed1988

Sustained release of the antimetabolite 5-fluorouridine-5'-monophosphate by multivesicular liposomes.

We have developed a novel liposome for sustained drug delivery to the eye of the antimetabolite 5-fluorouridine-5'-monophosphate (FUMP), a potent metabolite of 5-fluorouracil. The in vitro half-life of FUMP incorporated within these liposomes was 585 hours. Following subconjunctival administration of 1 mg of FUMP to 13 New Zealand white rabbits, the tissue drug level at the injection site was significantly greater in the group treated with liposomes than it was in the group not treated with liposomes (p = .02). These liposomes offer the potential for sustained release of FUMP in the eye. By controlling the rate of drug release, it may be possible to reduce the need for frequent drug administration and its associated ocular toxicity as well as to improve treatment efficacy.

Animals↗
PubMed1987

Methods for in situ visualization and assay of sulfurtransferases.

The dansyl derivative 5-dimethylamino-1-naphthalene thiosulfonate (DANTS) can serve as a sulfane sulfur-donor substrate for several of the sulfurtransferases, the reaction being dependent on the acceptor substrates supplied. Enzymatic cleavage of the sulfur-sulfur bond of DANTS releases the intrinsic fluorescence of the molecule, with an emission maximum of 500-510 nm (excitation at 325 nm). This process permits selective visualization of active sulfurtransferase enzymes separated in nondenaturing polyacrylamide gels, even from impure preparations. This technique was used to locate rhodanese (thiosulfate: cyanide sulfurtransferase, EC 2.8.1.1), thiosulfate reductase (EC unassigned), and a recently isolated prokaryotic enzyme that has been called sulfane sulfurtransferase. In addition, a refinement of the thiosulfate reductase assay technique is reported.

Dansyl Compounds↗
PubMed1987

Development of radioimmunoassays for human erythropoietin using recombinant erythropoietin as tracer and immunogen.

Since the estimation of erythropoietin (EPO) by radioimmunoassay (RIA) has been limited by the availability of highly purified urinary (U) human (Hu) EPO, we investigated the use of recombinant (R)-HuEPO as a replacement for U-HuEPO in the preparation of 125I-tracer and high affinity antisera. In each of two validated RIAs developed using U-HuEPO-derived reagents, dose-response lines and potency estimates for samples were compared when 125I-U-HuEPO and anti-U-HuEPO antisera were sequentially replaced to give assay variants using R-HuEPO-derived reagents. Two U-HuEPO preparations, the 2nd International Reference Preparation and CAT-1, and R-HuEPO were variously used as standards. The samples tested included clinically relevant human sera and partially purified preparations of U-HuEPO and R-HuEPO. In each RIA and for each assay variant tested, samples gave dose-response lines whose slopes did not differ significantly from that of the standard. For each of the two variant RIAs, potency estimates for any sample were consistent and, where examined, RIA potency estimates agreed with in vivo bioassay determinations. These results, obtained independently in two laboratories, indicate that RIAs having appropriate specificity and sensitivity for the estimation of EPO in clinical samples can be developed using reagents derived from R-HuEPO.

Biological Assay↗
PubMed1987

Local recurrence in adult soft-tissue sarcoma. A randomized trial of brachytherapy.

We conducted a prospective randomized study of the benefit of adjuvant radiation therapy delivered by the brachytherapy technique in 117 adult patients who had soft-tissue sarcoma that was on an extremity or superficially localized to the trunk. A significant decrease in local recurrence was demonstrated in the patients receiving brachytherapy. The benefit did not appear to be due to any maldistribution in the known prognostic factors of size, site, depth, presentation with recurrence, or histologic grade. The decrease in local recurrence appears to be due to the decreased local recurrence in high-grade sarcomas. Survival differences were not identified, and accrual and follow-up were continued.

Adult↗
PubMed1987

Binding the elderly: a prospective study of the use of mechanical restraints in an acute care hospital.

Little information exists on the use of mechanical restraints among nonpsychiatric inpatients. This prospective study evaluates their use among consecutive medical and surgical admissions to an acute care hospital. Daily direct observation of patients and hospital record review provided data on potential predictors of restraint, reasons for their application, complications, and outcome. Cox regression analysis was used to calculate relative risk of restraint while adjusting for duration of hospitalization as well as other variables. Restraints were applied to 37 (17%) of the 222 study patients. Restrained patients were eight times more likely to die during hospitalization (24% v 3%; P less than 0.01). Abnormal mental status exam, diagnosis of dementia, surgery, and presence of monitoring and support devices (eg, intravenous lines) were statistically significant independent predictors of restraint. Mechanical restraint is a common occurrence among nonpsychiatric inpatients particularly those with impaired mentation, requirement for surgery, or intensive medical intervention. Identification of medical and surgical patients at risk for restraint may reduce the use of these devices by concentrating surveillance and prevention on this group.

Aged↗